Bladder Tumor Location Matters: Trigone and Bladder Neck Involvement Predict Worse Oncological Outcomes in High-Grade Non-Muscle-Invasive Bladder Cancer.

Abstract

We aimed to evaluate the impact of bladder tumor location on oncological outcomes in high-grade non-muscle-invasive bladder cancer (NMIBC). The testing cohort included 1796 patients with high-grade NMIBC treated with transurethral resection of bladder tumor (TURBT) and adjuvant Bacillus Calmette-Guérin (BCG). The primary endpoints were high-grade recurrence-free survival (HG-RFS) and progression-free survival (PFS). Propensity score matching (PSM) was used to adjust for clinicopathological confounders between patients with and without trigone/bladder neck involvement. External validation included 20,249 high-grade NMIBC from the Surveillance, Epidemiology, and End Results (SEER) database, with overall and cancer-specific survival (CSS) as endpoints. Cumulative incidence functions and competing-risk regression models were used for survival analyses. Our multicenter cohort included 1796 patients, of whom, 1351 (75%) had high-grade T1, 869 (48%) had multiple tumors, and 637 (35%) had tumors arising from bladder neck or trigone. On multivariable analysis, trigone or bladder neck involvement (hazard ratio, HR: 1.24, 95% confidence interval, CI 1.02-1.49) was independently associated with worse HG-RFS. This was confirmed in a PSM analysis, which also showed worse PFS (HR: 1.45, 95% CI 1.00-2.09) and HG-RFS (HR: 1.40, 95% CI 1.08-1.82). In the SEER cohort, trigone (HR: 1.22, 95% CI 1.09-1.38) and bladder neck (HR:1.37, 95% CI 1.19-1.58) tumors were independently associated with worse CSS compared with other locations. Involvement of the bladder trigone or neck is an independent prognostic factor for worse oncological outcomes in high-grade NMIBC. Further studies are needed to elucidate underlying mechanisms and determine the clinical implications for treatment decision-making.